xref: /linux/drivers/net/vmxnet3/vmxnet3_xdp.c (revision 71dfa617ea9f18e4585fe78364217cd32b1fc382)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Linux driver for VMware's vmxnet3 ethernet NIC.
4  * Copyright (C) 2008-2023, VMware, Inc. All Rights Reserved.
5  * Maintained by: pv-drivers@vmware.com
6  *
7  */
8 
9 #include "vmxnet3_int.h"
10 #include "vmxnet3_xdp.h"
11 
12 static void
13 vmxnet3_xdp_exchange_program(struct vmxnet3_adapter *adapter,
14 			     struct bpf_prog *prog)
15 {
16 	rcu_assign_pointer(adapter->xdp_bpf_prog, prog);
17 }
18 
19 static inline struct vmxnet3_tx_queue *
20 vmxnet3_xdp_get_tq(struct vmxnet3_adapter *adapter)
21 {
22 	struct vmxnet3_tx_queue *tq;
23 	int tq_number;
24 	int cpu;
25 
26 	tq_number = adapter->num_tx_queues;
27 	cpu = smp_processor_id();
28 	if (likely(cpu < tq_number))
29 		tq = &adapter->tx_queue[cpu];
30 	else
31 		tq = &adapter->tx_queue[reciprocal_scale(cpu, tq_number)];
32 
33 	return tq;
34 }
35 
36 static int
37 vmxnet3_xdp_set(struct net_device *netdev, struct netdev_bpf *bpf,
38 		struct netlink_ext_ack *extack)
39 {
40 	struct vmxnet3_adapter *adapter = netdev_priv(netdev);
41 	struct bpf_prog *new_bpf_prog = bpf->prog;
42 	struct bpf_prog *old_bpf_prog;
43 	bool need_update;
44 	bool running;
45 	int err;
46 
47 	if (new_bpf_prog && netdev->mtu > VMXNET3_XDP_MAX_MTU) {
48 		NL_SET_ERR_MSG_FMT_MOD(extack, "MTU %u too large for XDP",
49 				       netdev->mtu);
50 		return -EOPNOTSUPP;
51 	}
52 
53 	if (adapter->netdev->features & NETIF_F_LRO) {
54 		NL_SET_ERR_MSG_MOD(extack, "LRO is not supported with XDP");
55 		adapter->netdev->features &= ~NETIF_F_LRO;
56 	}
57 
58 	old_bpf_prog = rcu_dereference(adapter->xdp_bpf_prog);
59 	if (!new_bpf_prog && !old_bpf_prog)
60 		return 0;
61 
62 	running = netif_running(netdev);
63 	need_update = !!old_bpf_prog != !!new_bpf_prog;
64 
65 	if (running && need_update)
66 		vmxnet3_quiesce_dev(adapter);
67 
68 	vmxnet3_xdp_exchange_program(adapter, new_bpf_prog);
69 	if (old_bpf_prog)
70 		bpf_prog_put(old_bpf_prog);
71 
72 	if (!running || !need_update)
73 		return 0;
74 
75 	if (new_bpf_prog)
76 		xdp_features_set_redirect_target(netdev, false);
77 	else
78 		xdp_features_clear_redirect_target(netdev);
79 
80 	vmxnet3_reset_dev(adapter);
81 	vmxnet3_rq_destroy_all(adapter);
82 	vmxnet3_adjust_rx_ring_size(adapter);
83 	err = vmxnet3_rq_create_all(adapter);
84 	if (err) {
85 		NL_SET_ERR_MSG_MOD(extack,
86 				   "failed to re-create rx queues for XDP.");
87 		return -EOPNOTSUPP;
88 	}
89 	err = vmxnet3_activate_dev(adapter);
90 	if (err) {
91 		NL_SET_ERR_MSG_MOD(extack,
92 				   "failed to activate device for XDP.");
93 		return -EOPNOTSUPP;
94 	}
95 	clear_bit(VMXNET3_STATE_BIT_RESETTING, &adapter->state);
96 
97 	return 0;
98 }
99 
100 /* This is the main xdp call used by kernel to set/unset eBPF program. */
101 int
102 vmxnet3_xdp(struct net_device *netdev, struct netdev_bpf *bpf)
103 {
104 	switch (bpf->command) {
105 	case XDP_SETUP_PROG:
106 		return vmxnet3_xdp_set(netdev, bpf, bpf->extack);
107 	default:
108 		return -EINVAL;
109 	}
110 
111 	return 0;
112 }
113 
114 static int
115 vmxnet3_xdp_xmit_frame(struct vmxnet3_adapter *adapter,
116 		       struct xdp_frame *xdpf,
117 		       struct vmxnet3_tx_queue *tq, bool dma_map)
118 {
119 	struct vmxnet3_tx_buf_info *tbi = NULL;
120 	union Vmxnet3_GenericDesc *gdesc;
121 	struct vmxnet3_tx_ctx ctx;
122 	int tx_num_deferred;
123 	struct page *page;
124 	u32 buf_size;
125 	u32 dw2;
126 
127 	dw2 = (tq->tx_ring.gen ^ 0x1) << VMXNET3_TXD_GEN_SHIFT;
128 	dw2 |= xdpf->len;
129 	ctx.sop_txd = tq->tx_ring.base + tq->tx_ring.next2fill;
130 	gdesc = ctx.sop_txd;
131 
132 	buf_size = xdpf->len;
133 	tbi = tq->buf_info + tq->tx_ring.next2fill;
134 
135 	if (vmxnet3_cmd_ring_desc_avail(&tq->tx_ring) == 0) {
136 		tq->stats.tx_ring_full++;
137 		return -ENOSPC;
138 	}
139 
140 	tbi->map_type = VMXNET3_MAP_XDP;
141 	if (dma_map) { /* ndo_xdp_xmit */
142 		tbi->dma_addr = dma_map_single(&adapter->pdev->dev,
143 					       xdpf->data, buf_size,
144 					       DMA_TO_DEVICE);
145 		if (dma_mapping_error(&adapter->pdev->dev, tbi->dma_addr))
146 			return -EFAULT;
147 		tbi->map_type |= VMXNET3_MAP_SINGLE;
148 	} else { /* XDP buffer from page pool */
149 		page = virt_to_page(xdpf->data);
150 		tbi->dma_addr = page_pool_get_dma_addr(page) +
151 				VMXNET3_XDP_HEADROOM;
152 		dma_sync_single_for_device(&adapter->pdev->dev,
153 					   tbi->dma_addr, buf_size,
154 					   DMA_TO_DEVICE);
155 	}
156 	tbi->xdpf = xdpf;
157 	tbi->len = buf_size;
158 
159 	gdesc = tq->tx_ring.base + tq->tx_ring.next2fill;
160 	WARN_ON_ONCE(gdesc->txd.gen == tq->tx_ring.gen);
161 
162 	gdesc->txd.addr = cpu_to_le64(tbi->dma_addr);
163 	gdesc->dword[2] = cpu_to_le32(dw2);
164 
165 	/* Setup the EOP desc */
166 	gdesc->dword[3] = cpu_to_le32(VMXNET3_TXD_CQ | VMXNET3_TXD_EOP);
167 
168 	gdesc->txd.om = 0;
169 	gdesc->txd.msscof = 0;
170 	gdesc->txd.hlen = 0;
171 	gdesc->txd.ti = 0;
172 
173 	tx_num_deferred = le32_to_cpu(tq->shared->txNumDeferred);
174 	le32_add_cpu(&tq->shared->txNumDeferred, 1);
175 	tx_num_deferred++;
176 
177 	vmxnet3_cmd_ring_adv_next2fill(&tq->tx_ring);
178 
179 	/* set the last buf_info for the pkt */
180 	tbi->sop_idx = ctx.sop_txd - tq->tx_ring.base;
181 
182 	dma_wmb();
183 	gdesc->dword[2] = cpu_to_le32(le32_to_cpu(gdesc->dword[2]) ^
184 						  VMXNET3_TXD_GEN);
185 
186 	/* No need to handle the case when tx_num_deferred doesn't reach
187 	 * threshold. Backend driver at hypervisor side will poll and reset
188 	 * tq->shared->txNumDeferred to 0.
189 	 */
190 	if (tx_num_deferred >= le32_to_cpu(tq->shared->txThreshold)) {
191 		tq->shared->txNumDeferred = 0;
192 		VMXNET3_WRITE_BAR0_REG(adapter,
193 				       VMXNET3_REG_TXPROD + tq->qid * 8,
194 				       tq->tx_ring.next2fill);
195 	}
196 
197 	return 0;
198 }
199 
200 static int
201 vmxnet3_xdp_xmit_back(struct vmxnet3_adapter *adapter,
202 		      struct xdp_frame *xdpf)
203 {
204 	struct vmxnet3_tx_queue *tq;
205 	struct netdev_queue *nq;
206 	int err;
207 
208 	tq = vmxnet3_xdp_get_tq(adapter);
209 	if (tq->stopped)
210 		return -ENETDOWN;
211 
212 	nq = netdev_get_tx_queue(adapter->netdev, tq->qid);
213 
214 	__netif_tx_lock(nq, smp_processor_id());
215 	err = vmxnet3_xdp_xmit_frame(adapter, xdpf, tq, false);
216 	__netif_tx_unlock(nq);
217 
218 	return err;
219 }
220 
221 /* ndo_xdp_xmit */
222 int
223 vmxnet3_xdp_xmit(struct net_device *dev,
224 		 int n, struct xdp_frame **frames, u32 flags)
225 {
226 	struct vmxnet3_adapter *adapter = netdev_priv(dev);
227 	struct vmxnet3_tx_queue *tq;
228 	int i;
229 
230 	if (unlikely(test_bit(VMXNET3_STATE_BIT_QUIESCED, &adapter->state)))
231 		return -ENETDOWN;
232 	if (unlikely(test_bit(VMXNET3_STATE_BIT_RESETTING, &adapter->state)))
233 		return -EINVAL;
234 
235 	tq = vmxnet3_xdp_get_tq(adapter);
236 	if (tq->stopped)
237 		return -ENETDOWN;
238 
239 	for (i = 0; i < n; i++) {
240 		if (vmxnet3_xdp_xmit_frame(adapter, frames[i], tq, true)) {
241 			tq->stats.xdp_xmit_err++;
242 			break;
243 		}
244 	}
245 	tq->stats.xdp_xmit += i;
246 
247 	return i;
248 }
249 
250 static int
251 vmxnet3_run_xdp(struct vmxnet3_rx_queue *rq, struct xdp_buff *xdp,
252 		struct bpf_prog *prog)
253 {
254 	struct xdp_frame *xdpf;
255 	struct page *page;
256 	int err;
257 	u32 act;
258 
259 	rq->stats.xdp_packets++;
260 	act = bpf_prog_run_xdp(prog, xdp);
261 	page = virt_to_page(xdp->data_hard_start);
262 
263 	switch (act) {
264 	case XDP_PASS:
265 		return act;
266 	case XDP_REDIRECT:
267 		err = xdp_do_redirect(rq->adapter->netdev, xdp, prog);
268 		if (!err) {
269 			rq->stats.xdp_redirects++;
270 		} else {
271 			rq->stats.xdp_drops++;
272 			page_pool_recycle_direct(rq->page_pool, page);
273 		}
274 		return act;
275 	case XDP_TX:
276 		xdpf = xdp_convert_buff_to_frame(xdp);
277 		if (unlikely(!xdpf ||
278 			     vmxnet3_xdp_xmit_back(rq->adapter, xdpf))) {
279 			rq->stats.xdp_drops++;
280 			page_pool_recycle_direct(rq->page_pool, page);
281 		} else {
282 			rq->stats.xdp_tx++;
283 		}
284 		return act;
285 	default:
286 		bpf_warn_invalid_xdp_action(rq->adapter->netdev, prog, act);
287 		fallthrough;
288 	case XDP_ABORTED:
289 		trace_xdp_exception(rq->adapter->netdev, prog, act);
290 		rq->stats.xdp_aborted++;
291 		break;
292 	case XDP_DROP:
293 		rq->stats.xdp_drops++;
294 		break;
295 	}
296 
297 	page_pool_recycle_direct(rq->page_pool, page);
298 
299 	return act;
300 }
301 
302 static struct sk_buff *
303 vmxnet3_build_skb(struct vmxnet3_rx_queue *rq, struct page *page,
304 		  const struct xdp_buff *xdp)
305 {
306 	struct sk_buff *skb;
307 
308 	skb = build_skb(page_address(page), PAGE_SIZE);
309 	if (unlikely(!skb)) {
310 		page_pool_recycle_direct(rq->page_pool, page);
311 		rq->stats.rx_buf_alloc_failure++;
312 		return NULL;
313 	}
314 
315 	/* bpf prog might change len and data position. */
316 	skb_reserve(skb, xdp->data - xdp->data_hard_start);
317 	skb_put(skb, xdp->data_end - xdp->data);
318 	skb_mark_for_recycle(skb);
319 
320 	return skb;
321 }
322 
323 /* Handle packets from DataRing. */
324 int
325 vmxnet3_process_xdp_small(struct vmxnet3_adapter *adapter,
326 			  struct vmxnet3_rx_queue *rq,
327 			  void *data, int len,
328 			  struct sk_buff **skb_xdp_pass)
329 {
330 	struct bpf_prog *xdp_prog;
331 	struct xdp_buff xdp;
332 	struct page *page;
333 	int act;
334 
335 	page = page_pool_alloc_pages(rq->page_pool, GFP_ATOMIC);
336 	if (unlikely(!page)) {
337 		rq->stats.rx_buf_alloc_failure++;
338 		return XDP_DROP;
339 	}
340 
341 	xdp_init_buff(&xdp, PAGE_SIZE, &rq->xdp_rxq);
342 	xdp_prepare_buff(&xdp, page_address(page), rq->page_pool->p.offset,
343 			 len, false);
344 	xdp_buff_clear_frags_flag(&xdp);
345 
346 	/* Must copy the data because it's at dataring. */
347 	memcpy(xdp.data, data, len);
348 
349 	xdp_prog = rcu_dereference(rq->adapter->xdp_bpf_prog);
350 	if (!xdp_prog) {
351 		act = XDP_PASS;
352 		goto out_skb;
353 	}
354 	act = vmxnet3_run_xdp(rq, &xdp, xdp_prog);
355 	if (act != XDP_PASS)
356 		return act;
357 
358 out_skb:
359 	*skb_xdp_pass = vmxnet3_build_skb(rq, page, &xdp);
360 	if (!*skb_xdp_pass)
361 		return XDP_DROP;
362 
363 	/* No need to refill. */
364 	return likely(*skb_xdp_pass) ? act : XDP_DROP;
365 }
366 
367 int
368 vmxnet3_process_xdp(struct vmxnet3_adapter *adapter,
369 		    struct vmxnet3_rx_queue *rq,
370 		    struct Vmxnet3_RxCompDesc *rcd,
371 		    struct vmxnet3_rx_buf_info *rbi,
372 		    struct Vmxnet3_RxDesc *rxd,
373 		    struct sk_buff **skb_xdp_pass)
374 {
375 	struct bpf_prog *xdp_prog;
376 	dma_addr_t new_dma_addr;
377 	struct xdp_buff xdp;
378 	struct page *page;
379 	void *new_data;
380 	int act;
381 
382 	page = rbi->page;
383 	dma_sync_single_for_cpu(&adapter->pdev->dev,
384 				page_pool_get_dma_addr(page) +
385 				rq->page_pool->p.offset, rbi->len,
386 				page_pool_get_dma_dir(rq->page_pool));
387 
388 	xdp_init_buff(&xdp, PAGE_SIZE, &rq->xdp_rxq);
389 	xdp_prepare_buff(&xdp, page_address(page), rq->page_pool->p.offset,
390 			 rbi->len, false);
391 	xdp_buff_clear_frags_flag(&xdp);
392 
393 	xdp_prog = rcu_dereference(rq->adapter->xdp_bpf_prog);
394 	if (!xdp_prog) {
395 		act = XDP_PASS;
396 		goto out_skb;
397 	}
398 	act = vmxnet3_run_xdp(rq, &xdp, xdp_prog);
399 
400 	if (act == XDP_PASS) {
401 out_skb:
402 		*skb_xdp_pass = vmxnet3_build_skb(rq, page, &xdp);
403 		if (!*skb_xdp_pass)
404 			act = XDP_DROP;
405 	}
406 
407 	new_data = vmxnet3_pp_get_buff(rq->page_pool, &new_dma_addr,
408 				       GFP_ATOMIC);
409 	if (!new_data) {
410 		rq->stats.rx_buf_alloc_failure++;
411 		return XDP_DROP;
412 	}
413 	rbi->page = virt_to_page(new_data);
414 	rbi->dma_addr = new_dma_addr;
415 	rxd->addr = cpu_to_le64(rbi->dma_addr);
416 	rxd->len = rbi->len;
417 
418 	return act;
419 }
420